Existing portable pipe cleaning machines (see, e.g., U.S. Pat. No. 4,188,683) have a drive power unit that is provided with a powered pipe shaft. Through this pipe shaft, a pipe cleaning coil will be inserted. Above and beyond that, these machines contain a clamp mechanism that is attached to the pipe shaft for the temporary stable coupling of the pipe shaft with the pipe cleaning coil in a temporary conveyance position; i.e. a position in which rotation is conveyed or transmitted to the pipe cleaning coil. A hand lever on the top of the drive housing unit is provided for the operation of the clamp mechanism for temporarily coupling the pipe shaft with the pipe cleaning coil. The hand lever is operated by one of the operator's hands during use.
The front end of the pipe cleaning coil is equipped with a tool designed to hit an obstruction present in a pipe or canal. In operation, when the tool hits an obstruction, the pipe cleaning coil is turned to the right or left in constant alteration to allow a further intrusion of the tool on the pipe cleaning coil against the obstruction. Heretofore, the changeable shifting of the turning direction of the pipe cleaning coil was achieved through the use of a switch that was affixed to the back of the housing unit for the power unit. In that situation, the switch was located outside of the real field of activity, namely on the back of the pipe cleaning machine in a position hard for the operator to reach. Because the operator must constantly lead the pipe cleaning coil with one hand out of the pipe shaft, in order to push the pipe cleaning coil into the pipe to be cleaned, and with the other hand must push the hand lever, every time the switch had to be touched the work procedure was interrupted. This was inconvenient and time consuming.